1. Field of the Invention
The present invention relates to an electrolysis gas converter according to electrochemical reaction using a solid polymer electrolytic film. Specifically, it relates to an electrolysis gas converter such as a generator of ozone gas, oxygen gas or hydrogen gas, dehumidifying device or the like, which converts water in air into ozone gas, oxygen gas, hydrogen gas or the like according to an electrochemical reaction, wherein a solid polymer electrolytic film is interposed between an anode and a cathode and wherein DC voltage is induced thereto. The converter is applied for a generator of ozone gas, oxygen gas or hydrogen gas, dehumidifying device or the like.
2. Description of Related Art
FIG. 12 is a construction view of an ozone generator which is one of the examples of conventional electrolysis gas converters disclosed, for example, in Japanese Unexamined Patent Publication No. 131276/1999. In FIG. 12, numeral 1 indicates an anode having a catalytic layer on anode base substrate comprising conductive porous material, numeral 2 indicates a cathode having a catalytic layer on cathode base substrate comprising conductive porous material, and numeral 3 indicates a solid polymer electrolytic film. A jointed electrochemical device 8 is formed by hot press with placing the anode 1 and the cathode 2 on both surfaces of the solid polymer electrolytic film 3. Numeral 4 is an anode terminal placed on the anode 1, numeral 5 is a cathode terminal on the cathode 2, numeral 6 is a DC power source, numeral 7 is a connection cable coupling the DC power source 6 with the anode 1 and the cathode 2.
For the anode 1, there is used, for example, a material formed by thinly electrodepositing xcex2 or xcex1 lead dioxide onto an expand metal substrate made of titanium having platinum-plated base. For the cathode 2, there is used a material formed by sticking a carbon powder carrying platinum particles onto a porous carbon fiber substrate using a liquefied solid polymer electrolyte as a binder.
Next, explanation is made as to operation. For example, when 3 V of DC voltage through a DC power 6 is induced to the jointed electrochemical device 8, water in air is electrolyzed at the jointed surface of the anode 1 and a solid polymer electrolytic film 3. Therefore, hydrogen ion is generated, ozone gas, oxygen gas and electrons are generated according to the electrochemical reaction formulas (1) and (2).
2H2Oxe2x86x92O2+4H++4exe2x88x92xe2x80x83xe2x80x83(1)
3H2Oxe2x86x92O3+6H++6exe2x88x92xe2x80x83xe2x80x83(2)
The thus generated ozone gas and oxygen gas are released outside through the porous anode 1.
On the other hand, the generated hydrogen ions move to the cathode 2 through the solid polymer electrolytic film 3. According to electrochemical reaction formula (3), the moved hydrogen ions react with the electrons led to the cathode 2 through oxygen gas in air and the connection cable 7 to generate water at the jointed surface of the cathode 2 and the solid polymer electrolytic film 3. And it is released outside through the porous cathode 2.
O2+4H++4exe2x88x92xe2x86x922H2Oxe2x80x83xe2x80x83(3)
When a jointed electrochemical device 8 is used for a device generating oxygen or dehumidifying, namely when the electrolysis gas converter corresponds to a oxygen gas generator or a dehumidifying device, there is used, for example, a material obtained by plating platinum onto a porous expand metal substrate made of titanium as the anode 1 of the electrochemical device 8, and it generates oxygen at the anode and water at the backside of the cathode. Also, when an electrochemical device 8 is used for generating hydrogen, namely when the electrolysis gas converter corresponds to a hydrogen gas generator, there is used, for example, a material obtained by plating of platinum onto a porous expand metal substrate made of titanium as the anode 1 and the cathode 2, and it generates hydrogen at the cathode.
As mentioned above, in case a conventional electrolysis gas converter is, for example, an ozone generator, it generates ozone gas by electrolysis of water in air with the jointed electrochemical device 8. For this reason, there was a problem that the ozone generation amount varies depending on outside humidity to provide an unstable ozone generation amount, and that too much ozone is generated when the humidity is increased.
FIG. 13 shows the result of experiments using the ozone generator shown in FIG. 12. It is a view illustrating influence of relative humidity against relationship between ozone generation amount and induced voltage, and between current density and the induced voltage. Each value of the ozone generation amount and the current density is based on per 1 cm2 of the electrochemical reaction part of the jointed electrochemical device 8 at 20xc2x0 C.
As shown in FIG. 13, the ozone generation amount and the current density are increased when outside humidity is increased, while the ozone generation amount is increased in accordance with increase of current which flows through the jointed electrochemical device 8. On the other hand, load resistance of the jointed electrochemical device 8 during electricity flow varies complicatedly in accordance with the outside humidity. However, under a constant humidity condition, when the voltage induced to the jointed electrochemical device 8 is at most 3 V, current flow is decreased to decrease in ozone generation amount.
In order to control the jointed chemical device 8 having such properties to the state that it does not extremely generate or decrease ozone gas, only inducing of a constant voltage is not sufficient. For example, when the voltage is set to 3 V, the ozone generation amount is 0.08 mg/hr/cm2 at relative humidity of 35% (shown as C in the figure), and 0.50 mg/hr/cm2 at relative humidity of 95% (shown as C in the figure), which means that it varies by as much as about 6 times. Also, when the voltage is set to 1.8 V, the ozone generation amount almost equals to zero at 35% of the relative humidity and 0.09 (mg/hr/cm2) at 95% of the relative humidity. In short, it is not appropriate to operate the jointed electrochemical device 8 under a fixed voltage condition.
Furthermore, other conventional electrolysis gas converters such as a dehumidifying device, an oxygen gas generator and a hydrogen gas generator have a problem that the gas conversion amount varies in accordance with outside humidity and gas conversion amount is unstable since they are designed similarly to the ozone generator to convert water in air into gas according to electrolysis with the jointed electrochemical device 8.
The present invention has been carried out in order to solve the above problems. The object of the present invention is to prepare an electrolysis gas converter which can maintain a stable gas conversion amount without excessive gas generation by using a simple controlling means even if outside air conditions change. Also, another object of the present invention is to obtain an electric device equipped with the electrolysis gas converter, which can maintain a stable gas conversion amount.
As a result of intensive study on relationship between gas conversion amount of the conventional electrolysis gas converter and current flowing through the jointed electrochemical device, and between the gas conversion amount and induced voltage, the present invention has been completed based on the findings that the gas conversion can be maintained to a fixed amount by supplying a fixed current through the electrochemical device.
The first gas converter of the present invention comprises a jointed electrochemical device, which is obtained by inserting a solid polymer electrolytic film between an anode and a cathode having a catalytic layer on a base substrate of conductive porous material, and which decomposes water in air by inducing DC current thereto, wherein the converter is equipped with a means for supplying a fixed current to the jointed electrochemical device.
The second electrolysis gas converter of the present invention is that in the first gas converter, the DC current is supplied through a rectification circuit from an alternating input and the means for supplying the fixed current flow is a condenser connected in series between the above alternating input and the above rectification circuit.
The third electrolysis gas converter of the present invention is that in the second gas converter, a device for controlling voltage induced to the jointed electrochemical device is connected in parallel to the above jointed electrochemical device.
The fourth electrolysis gas converter of the present invention is that in the first gas converter, the means for controlling the fixed current flow is a resistor connected in series between the jointed electrochemical device and a DC power source.
The fifth electrolysis gas converter of the present invention is that in the first gas converter, the jointed electrochemical device is used as an ozone generator.
The sixth electrolysis gas converter of the present invention is that in the second gas converter, the jointed electrochemical device is used as an ozone generator.
The seventh electrolysis gas converter of the present invention is that in the fourth gas converter, the jointed electrochemical device is used as an ozone generator.
The eighth electrolysis gas converter of the present invention is that in the first gas converter, the jointed electrochemical device is used as an oxygen gas generator.
The ninth electrolysis gas converter of the present invention is that in the second gas converter, the jointed electrochemical device is used as an oxygen gas generator.
The tenth electrolysis gas converter of the present invention is that in the fourth gas converter, the jointed electrochemical device is used as an oxygen gas generator.
The eleventh electrolysis gas converter of the present invention is that in the first gas converter, the jointed electrochemical device is used as a hydrogen gas generator.
The twelfth electrolysis gas converter of the present invention is that in the second gas converter, the jointed electrochemical device is used as a hydrogen gas generator.
The thirteenth electrolysis gas converter of the present invention is that in the fourth gas converter, the jointed electrochemical device is used as a hydrogen gas generator.
The fourteenth electrolysis gas converter of the present invention is that in the first gas converter, the jointed electrochemical device is used as a dehumidifying device.
The fifteenth electrolysis gas converter of the present invention is that in the second gas converter, the jointed electrochemical device is used as a dehumidifying device.
The sixteenth electrolysis gas converter of the present invention is that in the fourth gas converter, the jointed electrochemical device is used as a dehumidifying device.
The first electric appliance of the present invention comprises the first gas converter.
The second electric appliance of the present invention comprises the second gas converter.
The third electric appliance of the present invention comprises the fourth gas converter.